Absorbing and releasing energy

The idea

An electron moves to another shell by absorbing or releasing a fixed amount of energy equal to the difference between the energies of the two levels.

Up and down

An electron sits in the L shell of an atom. Later it is found in the M shell, which is farther from the nucleus.

What must happen for an electron to move to a shell with higher energy?

• It absorbs a fixed amount of energy
• It releases a fixed amount of energy
• Nothing, it just drifts there

Jump between shells

Use the buttons to move the electron one shell at a time.

A fixed amount of energy

The electron moves to another shell by taking in or giving out a fixed amount of energy. That amount equals the difference between the energies of the two shells.

An electron moves to another shell by absorbing or releasing a fixed amount of energy, equal to the difference between the energies of the two levels.

Notes

An electron moves to another shell by absorbing or releasing a fixed amount of energy, equal to the difference between the energies of the two levels.

Check yourself

An electron moves from the L shell to the M shell. What happens?

An electron falls from the M shell to the K shell. How much energy is released?

Where can an electron not revolve?

• It releases a fixed amount of energy. The M shell has higher energy than the L shell, so energy is absorbed to go there.
• Its energy does not change. The two shells have different energies, so the electron's energy changes.
• It absorbs a fixed amount of energy — correct. Yes!
• The difference between the energies of the two levels — correct. Yes!
• The energy of the M shell only. The amount equals the difference between the two levels, not the energy of one level.
• Any amount, it can vary. A fixed amount is released, equal to the difference between the two levels.
• In the K shell. The K shell is an allowed shell.
• In between the allowed shells — correct. Yes!
• In the L shell. The L shell is an allowed shell.